JPH0532640B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to cryogenic liquid storage tanks.

A conventional above-ground tank for storing low-temperature liquid has a structure as shown in FIG.

In other words, the tank A that stores liquid such as LP gas has a steel structure tank body A1, and the outer periphery of the tank body A1 is covered with a heat insulating material A2.
The outer periphery of the heat insulating material A2 is further covered with a protective layer A3 made of carbon steel or the like.

A liquid barrier B is arranged and formed around the tank A to prevent the low temperature liquid from flowing out.

In this case, if the available land is wide, it is possible to provide enough space around the tank and build a low dike around the outer periphery, but in order to make effective use of the narrow land, a high concrete dike can be built near Tank A. A dike must be constructed.

Conventional tanks formed in this way have the following drawbacks:

<B> The steel body A1 of tank A is made of an expensive steel material with no low-temperature brittle properties in order to prevent low-temperature breakdown, and its outer surface is covered with a heat insulating material A2, and the outer surface is coated with a material such as carbon steel. It is covered with a protective layer A3.

Therefore, the construction cost of the tank becomes very high.

<B> If the stored liquid in the low-temperature liquid storage tank leaks, the outermost carbon steel will undergo low-temperature destruction. Therefore, even though the outer peripheral surface is covered, it is essential to further install a liquid barrier B on the outside of the tank.

<C> The steel tank body A1 has a limited thickness, and the heat insulating material A2 and protective layer A3 cannot be expected to have sufficient strength, so they have the disadvantage of being vulnerable to impact when it comes to protecting them from flying objects.

An object of the present invention is to solve these problems and provide a low-temperature liquid storage tank that can reduce construction costs and has excellent safety.

That is, the present invention surrounds the outer periphery of a sealed concrete inner tank for storing low-temperature liquid with a sealed concrete outer tank, and the inner tank and the outer tank are structurally insulated, and there is a gap between the two tanks. relates to a low-temperature liquid storage tank that has a sealed space around the entire circumference between side walls.

Next, embodiments of the tank of the present invention will be described.

First, the tank 1 of the present invention is composed of an inner tank 2 and an outer tank 3, and each part will be explained below.

[B] Inner tank The inner tank 2 is a tank for storing low-temperature liquefied gas, etc., and is formed into a sealed body.

The side walls and bottom slab of the inner tank 2 are made of PC concrete or reinforced concrete.

One of the features of the present invention is that the tank body is made of concrete instead of steel.

The bottom plate 4 of the inner tank 2 is supported by steel pipe piles or PC piles 9.

The bottom plate 4 is formed to have a diameter larger than that of the inner tank 2.

A heater 41 is arranged inside the bottom plate 4 to prevent freezing.

Further, a roof 5 is integrally attached to the upper edge of the inner tank 2 to form a sealed space.

The roof 5 may be made of concrete like the inner tank 2, or may be made of a known material that is lighter than concrete.

Furthermore, an eaves 51 is provided on the peripheral edge of the roof 5 so as to protrude from the peripheral surface of the inner tank 2.

This room has insulation material 11 on the entire surface except for the roof 5.
A membrane 12 is installed through the holder to form a sealed body with excellent heat insulation, liquid tightness, and airtightness.

A vapor barrier 52 such as a steel plate is attached to the inner surface of the roof 5, and a roof insulation material 53 is placed on a deck plate suspended from the roof 5 to prevent heat input from the roof 5. Form.

For example, known glass wool can be used as the roof heat insulating material 53.

[B] Outer tank The outer tank 3 is a protective container that protects the inner tank 2 from flying objects and prevents the low-temperature storage liquid from flowing out.

The outer tank 3 is arranged so as to surround the outer periphery of the inner tank 2 and at a distance that is at least enough to allow a worker to pass around the outer tank.

One of the characteristics of the outer tank 3 is that it is formed of PC concrete and is mounted on a common bottom plate 4 with the inner tank 2 so that they are formed integrally.

The upper edge of the outer tank 3 and the eaves 51 extending from the upper edge of the inner tank 2 are connected over the entire circumference by a telescopic joint 13 made of a stainless steel plate or a copper plate.

As a result, a continuous space is formed between the inner tank 2 and the outer tank 3, and this space is filled with nitrogen gas or the like to form a gas chamber 6.

That is, the lower end of the outer tank 3 is formed integrally with the inner tank 2, but the upper end is formed to be structurally insulated so that only airtightness can be maintained via the expansion joint 13.

This is to store the storage liquid more safely without affecting the other when either one of the two 2 and 3 is destroyed.

In this embodiment, a protective layer 7 is formed by spraying or pouring known pearlite concrete or the like having excellent heat insulating properties on the inner wall of the outer tank 3 in the gas chamber 6 and on the 4 surfaces of the bottom plate.

However, the protective layer 7 is not necessarily required for tanks that store LPG.

The protective layer 7 is formed on the inner surface of the outer tank 3 in the inner tank 2.
This is to prevent temperature breakdown of the outer tank 3 via the protective layer 7 without rapidly transmitting the temperature of the low-temperature liquid to the outer tank 3 when the outer tank 3 is broken.

Next, the storage condition of the tank will be explained.

[B] Normal times Under normal conditions, low-temperature liquid is stored in the inner tank 2.

In this case, since the gas chamber 6 is formed around the inner tank 2, the effect as a vapor barrier is greatly improved, and the eaves 51 prevent rainwater from entering and keep the protective layer 7 dry at all times. condition can be maintained.

Furthermore, as shown in Fig. 2, even if the inner tank 2 contracts somewhat due to temperature changes, there is no need to worry about the shrinkage affecting the outer tank 3 because the inner tank 2 is not completely formed with the outer tank 3. I don't want to sleep.

Further, by periodically inspecting the inside of the gas chamber 6 and inspecting the inner walls of the inner tank 2 and the outer tank 3, further safety of the tank can be ensured.

[B] In the event of a leak If a crack occurs in the inner tank 2 and low temperature liquid flows out from the inner tank 2, the low temperature liquid will flow into the gas chamber 6.

If the outer tank 3 is simply made of concrete, there is a possibility that the temperature will be destroyed by sudden contact with the low-temperature liquid, but in the case of the tank of this embodiment, the inner wall of the outer tank 3 and the bottom plate 4 have insulation properties. Since the excellent protective layer 7 is formed, it is possible to absorb the thermal shock of the low-temperature liquid that has flowed out and prevent destruction.

Therefore, the outer tank 3 is not damaged by the temperature due to the protective layer 7, and the outflow of the liquid is completely prevented.

Furthermore, even if the inner tank 2 is destroyed due to an earthquake, etc., the expansion joint 1
3 can absorb destructive phenomena.

Since each embodiment of the present invention is as described above, the following effects can be expected.

<B> Since a protective layer with excellent heat insulation is formed between the inner tank and the outer tank, even if the low temperature liquid in the inner tank leaks out, the temperature of the outer tank can be prevented from breaking down.

<B> The inner tank itself was constructed of concrete instead of steel.

As a result, it is no longer necessary to construct the tank using only steel as in the past, and it can be constructed using concrete, which is cheaper than steel, reducing construction costs.

<C> Since a space was formed between the inner tank and the outer tank,
The tank can be inspected even while the inner tank is being filled with low-temperature liquid.

<d> Since the gas chamber is formed in the space between the inner tank and the outer tank, the heat insulation effect can be clearly improved compared to the conventional structure shown in FIG.

Furthermore, by checking the gas concentration in the gas chamber, leak detection can be easily and accurately performed.

<e> Rather than simply attaching a roof to the dike, it was constructed by forming a double structure of sealed tanks with a space between the tanks.

Therefore, it is possible not only to prevent the intrusion of rainwater and ensure the moisture resistance of the protective layer, thereby improving the heat insulating effect of the protective layer, but also to limit the diffusion of boil-off gas when the inner tank is destroyed.

<F> If the side walls and ceiling of the outer tank are made of an expandable joint structure, even if the inner tank is destroyed, the deformation force will not be directly transmitted to the outer tank.

Therefore, there is very little risk that the outer tank will be destroyed by the destructive force of the inner tank.

<G> Even if the inner tank is deformed due to temperature changes, since both tanks are insulated, the inner tank can be deformed and the outer tank will not be affected in any way.

<H> Since the insulating material made of glass wool can be hung on the underside of the roof, inexpensive carbon steel can be used as a barrier attached to the underside of the ceiling, and there is no need to use expensive nickel steel.

<li> Since the tank can be made of concrete, it has increased impact resistance and can prevent damage from flying objects.

[Brief explanation of the drawing]

Figure 1: An explanatory diagram of an embodiment of the tank according to the present invention, Figure 2: An explanatory diagram of the case where the inner tank is deformed, and Figure 3.
Figure: Illustration of a conventional tank. 1: Tank, 2: Inner tank, 3: Outer tank, 4: Bottom plate,
5: Roof, 6: Gas chamber.

Claims (1)

[Scope of Claims] 1. The outer periphery of a sealed concrete inner tank for storing low-temperature liquid is surrounded by a sealed concrete outer tank, and the inner tank and the outer tank are structurally insulated, and both A low-temperature liquid storage tank with a sealed space between the tanks around the entire circumference between the side walls.